LITTLE known Jozef Kovalik caused the biggest upset of the Chennai Open as he knocked out world number six and tournament-favourite Marin Cilic in a gripping pre-quarterfinal, here on Wednesday.

Qualifier Kovalik, winner of just two Challenger titles in his career, was up against a Grand Slam winner but made Cilic’s life as tough as possible with his never-say-die spirit and in the end was a proud winner. Kovalik, ranked 117, showed nerves of steel in a hard-earned 7-6(5), 5-7, 7-5 win over the ‘rusty’ top seed.

Cilic, who ended the 2016 season with a career-best rank of six, was pushed by the Slovakian in two hours and 48 minute match and was rewarded with the biggest win of his career.

The 24-year-old Slovak refused to be in awe of a superior opponent and impressed with his ground-strokes. He had nothing to lose and everything to gain as he threw everything back at Cilic, who has won this tournament twice (2009, 2010).

Kovalik next faces Daniil Medvedev, who shocked eighth seed Yen-Hsun Lu 6-4 6-3 in his second round.It is first time since 2010 that a top seed has lost his first match after Robin Soderling had lost to Robby Ginepri.The Slovak said it was hard to believe that he has won against a top guy but it gives him confidence that he can match them.

“It’s a new experience for me to beat a top guy. This is the best match I have played in my career.